Metallization processes in general are well known and have been used for an extended period in various industries. For example, in the food and tobacco industries, there are numerous products which are wrapped in metallized liners to preserve freshness, to protect against environmental factors such as radiation, or to improve the aesthetics of packaging. Similarly, in the greeting card and decorative wrapping industries, metallized substrates have been used to provide unique designs of various types.
One such metallization process has been described in U.S. Pat. No. 4,215,170, the teachings of which are incorporated herein by reference. U.S. Pat. No. 4,215,170 is owned by the asignee of the instant application.
The method of U.S. Pat. No. 4,215,170 is directed to providing a smooth specular surface that is independent of the smoothness of the substrate or the metal, without the need for pretreatment of the substrate, and without exposing the substrate to a vacuum. The method involves depositing an extremely thin coat of metallic particles on a transfer agent. A thin coat of varnish is applied to either the substrate or transfer agent, and the two are laminated together before the varnish has cured. The metallic particles are absorbed or embedded within the varnish coat, which will provide the substrate with the appearance of a specular metallic finish. After the varnish has cured, the transfer agent and substrate are separated.
However, even though the method described in U.S. Pat. No. 4,215,170 was a substantial improvement over prior art metallization methods, it did not provide for the selective metallization of a substrate in order to provide decorative patterns, or to provide metallization in selected areas in order to reduce expense while retaining the effectiveness of the inventive metallization process.